Stereotype-matrix.



lso

GLENN S. WILLIAMSON, OF NEW YORK, N. Y.

STEREOTYPE-MATRIX.

1,173,907. No Drawing.

To all whom it may concern Be it known that I, GLENN S. WILLIAM- SON, acitizen of the United States, residing at New York, in the county of NewYork and State of New York, have invented certain new and usefulImprovements in Stereotype-Matrices, of which the following is aspecification.

This invention relates to matrices for use in the casting of stereotypeor similar plates commonly employed in the art of printing.

Such matrices have been heretofore molded fromv paper or other suitablefibrous material, previously impregnated with such condensation productsof phenols and formaldehyde as may be rendered infusible by heat, thecondensation product being transformed during or after the act ofmolding into a hardand infusible condition.

I have found that matrices of the above general character may berendered more resistant to the eifects of molten stereotype metal athigh temperatures, more servlceable, and in general more efiicient underthe usual working conditions, by using in conjunction with phenoliccondensation products of the character above mentioned, .certainstructureless salts or compounds, which although soluble in water arerefractory at the casting temperature of stereotype metal, say 550Fahrenheit. Of such compounds I believe the most suitable to be thesilicates of the alkali metals, and particularly sodium silicate, andthe corresponding aluminates, particularly sodium aluminate.

The preparation of matrices in accordance with the present invention maybe carried out as follows: A highly absorptive paper, as for example aheavy blotting paper, is first saturated by dipping or otherwise, with astrong solution of commercial sodium silicate, a twenty-five per cent.solution being suitable. The paper is then pressed to remove excesssolution and is thereafter dried, for instance in a current of warm air.The dry sheets, which are still highly absorbent, are then furtherimpregnated with a solution of a condensation product of phenols andformaldehyde, the condensation product used being such as is capable oftransformation by heat into an infusible body.

A condensation product of this kind may be prepared in accordance withany of the methods known to the art, or as follows: To 1000 grams ofphenol are added 40 grams of caustic soda dissolved in 100 grams ofSpecification of Letters Patent.

water, and 900 grams of 40 per cent. commercial formaldehyde, and themixture is boiled in a suitable vessel, preferably provided with a retun condenser, for about one hour, then quickly cooled. The liquid thusobtained may be suitably diluted by Patented Feb. 29, 1916.

Application filed May 27, 1912. Serial No. 700,054.

the addition of water or other solvent, either before or after theboiling process. 7

The impregnation should be so conducted asto load the aper approximatelyto its full capacity with the dissolved condensation product. It ispreferable to impregnate the sheet two or more times with thecondensation product, with a partial or complete drying between theimpregnations, in order that it may take up as much of the condensationproduct as practicable. After the final drying the paper is gentlyheated to convert the condensation product into the so-calledintermediate state, wherein it retains a considerable degree ofplasticity but is no longer completely soluble. One effect of thepreliminary saturation of the paper with sodium silicate is materiallyto reduce the time required for this conversion; heating to about 70 C.for a period of fifteen minutes or somewhat more will usually be foundsulficient in the case of paper which has been first impregnated withthe sodium silicate solution, whereas in the case of paper which has notbeen so treated it may be necessary to heat it for an hour or more inorder to effect the desired change. The mat or blank is now preferablyfurther strengthened by pasting on to one side of the sheet areinforcing sheet of comparatively thin and strong paper such as sisalpaper; for attaching this reinforcing sheet' I preferably use sodiumsilicate solution, whereby an additional proportion of this salt isincorporated. After again drying, ifnecessary, the opposite face of thesheet, which is to constitute the molded face of the matrix, is polishedby means of baryta, talc or other suitable material; or this face of thesheet is otherwise given a smooth and non-absorbent surface, as forexample by applying thereto a thin sheet of paper of finer texture, suchfor instance as tissue or the so-called onion-skin paper.

The sheet, impregnated and dried as above described, is now molded in apress, heated by steam or otherwise, by forcing it against the type orother matter to be reproduced. Under ordinary circumstances, and using atemperature approximating 180 0., the

sheet should be held in the mold for approximately one minute, althoughgood results are obtainable with longer or shorter heating periods. Itis merely necessary to heat in the press long enough to secure the whichmight interfere with the further operation of casting the molten metal.

For ordinary press work, a flat scorcher may be used, that is to say ahot plate, heated by any suitable means, and upon which the matrix isplaced for a short time, or

until a condition of hardness sufliciently approximating the maximum isattained.

In case a curved matrix is desired, as for rotary press work, it shouldof course be adapted in curvature to the requirements of the castingmachine and press used. While the necessary curvature may be imparted atany stage of the process before the condition of ultimate hardness isreached, it has prov'en satisfactory in practice to curve the matrixduring the scorching process above referred to. The matrix should betrimmed and transferred to the curved scorcher immediately after moldingand While it still retains a considerable degree of plasticity. Suchscorcher may be heated by gas flames. or electrically or otherwise asmay be preferred.

A modified procedure which is preferred under some conditions is asfollows: The blotting paper is impregnated with a liquid condensationproduct as before described, and is then baked for an hour, more orless, at about Centigrade. The sheet is then dipped or otherwiseimpregnated with a fifty per cent. solution of sodium silicate, and isthereafter thoroughly dried at normal or somewhat higher temperatures.It is then baked for fifteen minutes. at seventy degrees. The sheet isthen faced with thin paper, as for example sisal paper, pasted on withsodium silicate solution, and is also backed with from one to threesheets of a similar light, strong paper, also applied with sodiumsilicate solution. The compound sheet thus prepared is then dried andmolded in the manner above described.

Matrices prepared by the above methods have been found well adapted towithstand the action of type metal'introduced under pressure and attemperatures of 550 F. or upward, without any necessity for extensiveso-called backing up which has for its purpose the reinforcement of theblank or. rojecting areas of the matrix As w' be readily understood bythose familiar with this art, this results in a most important saving oftime at the very period when such saving is most advantageous, that isto say after the moldin of the matrix.- Blank areas of unusually argesize may require backing up, but the great bulk of this work asheretofore invariably required, is eliminated. 7

It appears that the phenolic condensation product, by reason of itsinitial plasticity and its capability of ultimate transformation into aninfusible and non-plastic state,

serves to receive and retain the impression of the type, and also toharden and strengthen the finished matrix; whereas the sodium silicateor other suitable. inorganic body acts as a reinforcing-agent,especially during the earlier stages of the process, while the phenoliccondensation product is yet in its plastic condition.

In the above specification, as well as in the following claims, the wordphenols is meant to designate not only the first mem: ber of the phenolgroup, but its homologues and isomers, or phenolic bodies, or mixturesthereof, which are equivalent in this reaction. And in the same way thepolymers of formaldehyde, hexamethylentetramin, or substances which mayengender formaldehyde, or which are equivalent thereto in this reaction,may be used as equivalents of formaldehyde.

The invention is not restricted to the parthat other salts, compounds,or inorganic bodies, preferably structureless, which are soluble inwater but are refractory in a solid state in presence of moltenstereotype or linotypemetal, or similar alloys, may be substitutedtherefor and may be equivalent thereto for the purposes of thisinvention.

Salts or compounds which are basic in character or which have analkaline reaction. in aqueous solution are preferred, since by their usethe baking and molding processes appear to be materially accelerated.

I claim: v

1. A mat or blank for molding stereotype and similar matrices,comprising a fibrous sheet containing a plastic organic body which ishardened and rendered infusible by a chemical transformation occurringunder the action of heat, and a reinforcing- .inforcing agents, inasmuchas it is possible is refractory in the presence of molten stereotype orlinotype metal, and a plastic organic body which is hardened andrendered infusible by a chemical transformation occurring under theaction of heat.

3. A. mat or blank for molding stereotype and similar matrices,comprising a fibrous material impregnated with a structureless inorganicbody which .in the solid state is refractory in the presence of moltenstereotype or linotype metal, and with a plastic phenolic condensationproduct which is capable of transformation by heat into an infusibleproduct.

4. A mat or blank for molding stereotype .and similar matrices,comprising fibrous material impregnated with a silicate of an valkalimetal and a plastic phenolic condensation product which is capable oftransformation by heat into an infusible product.

5. A. matrix for metallic stereotype and similar plates, comprisingfibrous material containing a structureless inorganic body which in thesolid state is refractory in the presence of molten stereotype orlinotype metal, and an infusible phenolic condensation product.

6. A matrix for metallic stereotype and similar plates, comprising afibrous material containing a silicate of an alkali metal and aninfusible phenolic condensation product.

7 The method of making stereotype and similar matrices, which consistsin impregnating a fibrous material with a structureless inorganic bodywhich in the solid state is refractory in the presence of moltenstereotype or linotype metal, and with a plastic phenolic condensationproduct, and molding the composition under heat and pressure, wherebysaid condensation product is transformed into an infusible body.

8. The method of making stereotype and similar matrices, which consistsin impregnating a fibrous material with a silicate of an alkali metal,and with a plastic phenolic condensation product, and molding thecomposition under heat and pressure, whereby the said condensationproduct is transformed into an infusible body.

9. The method of making stereotype and similar matrices, which consistsin impregnating a fibrous material successively with a structurelessinorganic body which in the solid state is refractory in the presence ofmolten stereotype or linotype metal, and with a plastic phenoliccondensation product, and molding the composition under heat andpressure, whereby said condensation product is transformed into aninfusible body.

10. The method of making stereotype and similar matrices, which consistsin impregnating a fibrous material successively with a silicate of analkali metal and with a plastic phenolic condensation product andmolding the composition under heat and pressure, whereby the saidcondensation product is transformed into an infusible body.

In testimony whereof I afiix my signature in presence oftwo witnesses.

GLENN S. WILLIAMSON.

Witnesses:

PAUL LAUGERFELD, EDMUND D. TITUS.

